The die off was the disaster, otherwise the LMB may have kept up with them. This is going to sound odd ... but since you haven't stocked yet and you like crappie ... consider a surrogate since you are west of the continental divide. The sacramento perch may be an option. You may not even need a predator as it was the apex predator over much of its native range before the introduction of non-native centrarchid. They won't recruit well if you stock other centrarchids with them and may extirpate. They have been very difficult to establish where there are other centrarchids and most introductions have failed. But as standalone ... they may do very well. Worst case, stock other things and they will go away ... but if they recruit and grow well, you'd had a pond of crappie-like fish that are much less likely to over populate.
